Reanalysis of Additional Selected Archived NURE-HSSR Sediment Samples from Idaho and Montana

In December of 2018, the U.S. Geological Survey (USGS) signed a Technical Assistance Agreement with a third party to reanalyze 2,324 archived sample splits collected as part of the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) project from selected areas in Idaho and Montana. A small amount (approximately 0.25 grams [g]) of sieved less than 75-micron sample material was retrieved from the USGS National Geochemical Sample Archive for geochemical analysis. These samples were analyzed for 48 elements by ALS Global laboratories using their ultra-trace four-acid-digestion dual-mode inductively coupled plasma mass spectrometry (ICPMS) (ALS ME-MS61L) method (Ag, Al, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, In, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, Re, S, Sb, Sc, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn, Zr). These data are comparable to those reported by Smith and others (2018, 2019). A subset of these samples, as identified by the collaborating party, was additionally analyzed by ALS Global laboratories for stable lead isotopes (204Pb, 206Pb, 207Pb, and 208Pb).